[Functionality] add localized `license-page` context(s)

## Problem

The license pages are not included as `contexts` within `index-prototype`, and cannot be tested against reliably.

## Description
At current the license pages for the legal code and the deed pages are stylized, but are variants of, existing contexts with hyper localized stylings of their own.

### html:
* `deed:` https://creativecommons.org/licenses/by-nc-nd/4.0/deed.en, uses `walkthrough-page` context
* `license:` https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode.en, uses `default-page` context

### css:
* `base.css:` https://github.com/creativecommons/cc-legal-tools-app/blob/3bc446c0343733506f8cd54ca1173654b8cdfac6/cc_legal_tools/static/cc-legal-tools/base.css
* `deed.css:` https://github.com/creativecommons/cc-legal-tools-app/blob/3bc446c0343733506f8cd54ca1173654b8cdfac6/cc_legal_tools/static/cc-legal-tools/deed.css
* `legalcode.css:` https://github.com/creativecommons/cc-legal-tools-app/blob/3bc446c0343733506f8cd54ca1173654b8cdfac6/cc_legal_tools/static/cc-legal-tools/legalcode.css

Despite the use of existing contexts, there are several sub-elements and stylings which do not pull from vocabulary core at this time. Neither page exists as a context within this repository, but should. For now, work should start here, and after being finalized it might be possible to generalize it back to a vocabulary core context, for now, it's existence as production markup+styling without a corresponding index-prototype context is out of process, and difficult to both build for and test.

This should be either:
* one generalized local context, such as: `license-page`
* two similar, but distinct local contexts: `deed-page`, `legalcode-page`

## Alternatives
There is also a case that this should be a possibility within a robust enough `walkthrough-page` context, but it does not fully exist yet.

## Implementation

- [x] I would be interested in implementing this feature.